[en] Purpose: To determine the best treatment technique for patients with retinoblastoma requiring radiotherapy to the whole eye. Methods and Materials: Treatment plans for 3 patients with retinoblastoma were developed using 10 radiotherapy techniques including electron beams, photon beam wedge pair (WP), photon beam three-dimensional conformal radiotherapy (3D-CRT), fixed gantry intensity-modulated radiotherapy (IMRT), photon volumetric arc therapy (VMAT), fractionated stereotactic radiotherapy, and helical tomotherapy (HT). Dose-volume analyses were carried out for each technique. Results: All techniques provided similar target coverage; conformity was highest for VMAT, nine-field (9F) IMRT, and HT (conformity index [CI] = 1.3) and lowest for the WP and two electron techniques (CI = 1.8). The electron techniques had the highest planning target volume dose gradient (131% of maximum dose received [D_max]), and the CRT techniques had the lowest (103% D_max) gradient. The volume receiving at least 20 Gy (V_20Gy) for the ipsilateral bony orbit was lowest for the VMAT and HT techniques (56%) and highest for the CRT techniques (90%). Generally, the electron beam techniques were superior in terms of brain sparing and delivered approximately one-third of the integral dose of the photon techniques. Conclusions: Inverse planned image-guided radiotherapy delivered using HT or VMAT gives better conformity index, improved orbital bone and brain sparing, and a lower integral dose than other techniques.

[en] Background: The pediatric diffuse intrinsic pontine glioma (DIPG) outcome remains dismal despite multiple therapeutic attempts. Purpose: To compare the results of treatment of pediatric diffuse intrinsic pontine glioma (DIPG) using hypofractionated versus conventional radiotherapy. Patients and methods: Seventy-one newly diagnosed DIPG children were randomized into hypofractionated (HF) (39 Gy/13 fractions in 2.6 weeks) and conventional (CF) arm (54 Gy/30 fractions in 6 weeks). Results: The median and one-year overall survival (OS) was 7.8 months and 36.4 ± 8.2% for the hypofractionated arm, and 9.5 and 26.2 ± 7.4% for the conventional arm respectively. The 18-month OS difference was 2.2%. The OS hazard ratio (HR) was 1.14 (95% CI: 0.70–1.89) (p = 0.59). The hypofractionated arm had a median and one-year progression-free survival (PFS) of 6.6 months and 22.5 ± 7.1%, compared to 7.3 and 17.9 ± 7.1% for the conventional arm. The PFS HR was 1.10 (95% CI: 0.67–1.90) (p = 0.71). The 18-month PFS difference was 1.1%. These differences exceed the non-inferiority margin. The immediate and delayed side effects were not different in the 2 arms. Conclusions: Hypofractionated radiotherapy offers lesser burden on the patients, their families and the treating departments, with nearly comparable results to conventional fractionation, though not fulfilling the non-inferiority assumption